Mad cow disease in the United States: An update on bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease

Abstract

Classified among the transmissible spongiform encephalopathies, bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD), are neurodegenerative conditions associated with the accumulation of an abnormal protein called PrP. Both conditions are thought to result from a novel type of infection that is mediated by a protein agent rather than a nucleic acid-containing particle. Amplified by the practice of feeding infected bovine tissue to other cattle, the BSE epidemic in the United Kingdom has now been largely controlled; BSE has, however, spread to other countries. Multiple lines of evidence support the hypothesis that BSE and vCJD are caused by the same agent. In the United States, a variety of measures have been implemented to survey for BSE and to prevent the development of an epidemic in this country. The recent identification of the first case of BSE in the U.S. has increased interest in these areas.